If I had it three months ago I'm not infectious now.
If you had it 3 months ago, you are not infectious now. The "infectability of the virus " the virologists say is about 14 days....about 5-7 days until you show symptoms and about a week after that.
Beth might tell us differently but I don't think anyone knows how long immunity if it exists lasts for
This is a very different question Kiwi. This indicates you have raised antibodies to the virus, so it is a good marker that you have had it.
The question you ask is "are you immune?".
OK....if you raise antibodies you are probably immune (protected) or partially immune (partially protected). What I mean is that if the virus infects again, you will have only mild symptoms .
But how long do these antibodies last is the question that scientists do not know. There is evidence from China that they don't last long ( say3-6 months).....for herd immunity or a vaccine to work , we would like them to last year or 5 or better still a life time.
Now I am going to get heavy duty scientific, so new readers cut off her.
In your body you have things called memory B cells, these are white blood cells and they carry in them the apparatus to raise antibodies to any bad thing (pathogen) you have ever seen, they are at an incredibly low level ...but they are there, in nearly all of us. So when we see the pathogen a second time...the expand rapidly and start making the protective antibody again. So it is hoped that even if your antibody levels fall ( below detection levels) these memory B cells will still come to your aid
My reference to "detection levels" is also relevant. Our tests have a certain level of detection (in the chinese test is actually very poor). You may have really good antibodies but we can't detect them...with improving tests we will have new ideas of who has and who has not got antibodies...and we may see the antibodies last longer than the Chinese say they do
One final point:- not all antibodies are equal. Your body will make antibodies to the whole Covid19 virus, but not all antibodies will cause it to be killed. There are protective antibodies and there are more neutral antibodies. Some people will make protective antibodies which bind and cause killer T cells to destroy the virus...other may not, or to lesser degree...
And that is the point of testing the vaccine, all the vaccines will probably get the body to raise some sort of antibody response...we need the vaccine to make protective antibodies
Sorry if that is a bit heavy..
